1. Field of the Invention
The present invention relates to a magnetic tape cassette, particularly, the invention relates to a magnetic tape cassette including an urging plate spring for urging a tape reel, to one including a tape reel in use for a magnetic tape cartridge having reel a hub to be wound with a magnetic tape, to one including a reference positioning means, to one including a guide roller for guiding a magnetic tape, and to one including a cassette case having an information presenting section.
2. Description of the Related Art
A magnetic tape cassette which effects the recording/playing-back operation with such an arrangement that a magnetic tape wound on a couple of tape reels, while allowing its run, is held within a cassette case, is generally employed in many audio and video devices.
FIG. 3 is an exploded view showing a DVC (digital video cassette), which is one example of the magnetic tape cassette. A magnetic tape cassette 50 includes an upper cassette half 51 and a lower cassette half 52, each having a flat plate and a periphery wall. Those halves 51 and 52 are coupled together a plurality of screws 54. A couple of tape reels 60, each consisting of an upper flange and a lower flange, which are welded together, are rotatably supported within the lower cassette half 52 in a state that a magnetic tape 57 is wound on those tape reels.
Tape guides 55 are respectively provided on both sides of an opening 56 of the front side (this side in the figure) of the lower cassette half 52. The tape guides 55 guide the magnetic tape 57, which is fed from one of the tape reels 60 and taken up by the other, and moves the magnetic tape 57 through a predetermined position in the opening 56.
To secure the dust-proof performance high enough to withstand the outdoor condition, an outer lid 53a, an upper lid 53b and an inner lid 53c, which are lid members for covering the magnetic tape 57 tensioned between the couple of the tape guides 55 of the lower cassette half 52, are mounted on the front end of the upper cassette half 51 in a state that those may be opened and closed.
An opening is formed in the flat plate of the upper cassette half 51 such that it is covered with a transparent member 58.
Reel urging plate springs 70 are provided on a flat plate of the upper cassette half 51, while being respectively associated with the tape reels 60. The reel urging plate springs 70 are fastened to the upper cassette half 51, and urge the associated tape reels 60 toward the lower cassette half 52. As a result, the tape reels 60 are not shaky within the upper and lower cassette halves 51 and 52.
FIG. 4 is a diagram showing how the reel urging plate springs 70 urge the tape reels 60. Each the tape reel 60 includes a cylindrical hub 61 on which a magnetic tape is to be wound, a disc-like upper flange 62 provided on one end (the upper end in the figure) of the hub 61, and a disc-like lower flange 63 provided on the other end of the hub 61. A pivot 64 is provided at the center of the upper surface of the hub 61. The hub 61 serves as a contact part which comes in contact with the reel urging plate spring 70. In this instance, the hub 61, the lower flange 63 and the pivot 64 are formed in a one-piece construction.
A welding boss 65 is provided around the pivot 64. The upper flange 62 is welded on the upper surface of the hub 61 in such a manner that a welding horn (not shown) is brought into contact with the upper surface of the hub 61 in a state that the pivot 64 and the boss 65 are fit into the pivot and boss holes of the associated upper flange 62.
The top end of the pivot 64 is protruded above the upper surface of the upper flange 62. The reel urging plate spring 70 is fastened at its base to the flat plate of the upper cassette half 51 (see FIG. 3), and with its tip 70a, the top end of the pivot 64 is urged to the lower cassette half 52.
The lower flange 63, the hub 61 and the pivot 64 are made of resin of high rub resistance, e.g., polyoxymethylene (POM), in order to be durable when it is brought into contact with the drive shaft of a recording/playing-back device (not shown), the lower cassette half 52 (see FIG. 3) when the magnetic tape cassette drops, and the reel urging plate spring 70
The upper flange 62 is made of resin, which is cheaper in cost and inferior in rub resistance than POM. Example of such resin are acrylonitrile-butadinene-styrene (ABS) and polystyrene (PS).
If the lower flange 63, the hub 61 and the pivot 64 of each tape reel 60 are made of cheap resin with an intention of cost reduction of the magnetic tape cassette, the following problems arise.
Firstly, the tip of the pivot 64 made of cheap resin will be worn away through its contact with the reel urging plate spring 70 to produce cut powder since the rub resistance of the cheap resin is inferior to POM or the like. The cut powder thus produced will cause drop-out trouble and hinder smooth rotation of the tape reels 60.
One possible solution to this problem is that the lower flange 63 and the hub 61 are one-piece molded using cheap resin, and a hub 61 made of POM or the like is assembled into the hub 61. This approach, however, does not lead to the cost reduction of the magnetic tape cassette. Further, in a magnetic tape cassette, such as DVD or 8 mm cassette, in which the diameter of the hub 61 is small, it is difficult to use a separate pivot in manufacturing the tape cassette.
Next, a tape reel 106 of the magnetic tape cartridge, as shown in FIG. 9, includes a cylindrical reel hub 110 on which a magnetic tape 108 is wound, and a couple of upper and lower flanges 112 and 113 which are provided in the form of collars at the upper and lower ends of the reel hub 110 and position both side edges of the magnetic tape 108 wound on the reel hub 110.
In the tape reel 106 discussed here, as shown in FIG. 10, the upper flange 112 is integrally coupled to the upper end of the reel hub 110. The lower flange 113 and the reel hub 110 are joined together in a manner that a lib 113a protruded from the inner peripheral edge thereof is welded, by ultrasonic wave welding, to a step 110a formed along the peripheral edge of the lower end of the reel hub 110.
A new technique for increasing a recording density of a magnetic tape, which is contained in the magnetic tape cartridge, is disclosed in Japanese Patent Unexamined Publication No. Hei. 8-30932(JP-A-8-30932), for example. The technique is a magnetic tape writing system in which the operations of reading data from and writing data onto a magnetic tape are controlled in accordance with servo patterns written in the magnetic tape in advance
In the magnetic tape writing system, servo tracks for storing servo patterns indicative of tape position information and data tracks for storing data are arranged in the tape width direction. The reading/writing operations by the magnetic head is controlled in accordance with servo patterns written in the magnetic tape.
FIGS. 11 and 12 show constructions including a write head and its vicinities in a servo pattern writer, which writes or records servo patterns onto the magnetic tape used in the magnetic tape writing system.
Guide posts 123 and 124 for guiding the magnetic tape 108 to a write head 121, as shown in FIG. 11, are provided on both sides of the write head 121 for recording servo patterns. An arrow X in FIGS. 11 and 13 indicates a traveling direction of the magnetic tape 108.
In the illustrated example, as shown in FIG. 12, five servo tracks T11 to T15 for storing servo patterns are arranged at fixed spatial intervals in the tape width direction. Four regions each located between the adjacent servo tracks are used as data tracks T21 to T24 for storing data. Those data tracks T21 to T24 are each further divided into a plurality of narrow tracks (not shown).
The write head 121, as shown in FIG. 12, includes five gaps G1 to G5 used for recording servo patterns, which correspond in position to the servo tracks T11 to T15 on the magnetic tape 108.
Block patterns P1 and P2 each consisting of a plurality of slanted linear magnetized regions are formed in each of the servo tracks T11 to T15 as shown in FIG. 13. Servo patterns written into the linear magnetized regions of the block patterns P1 and P2 enable one to know positions on the magnetic tape. The writing/reading operation of data to and from the data regions is performed on the basis of the position information.
The writing of servo patterns into servo tracks T11 to T15 is carried out when the magnetic tape is initialized in the manufacturing process of the magnetic tape. In this case, servo patterns are written onto the magnetic tape over its entire length by use of a servo pattern writer, which is designed for servo pattern writing.
In the magnetic tape writing system, the data track regions may be managed more discretely and accurately. Accordingly, the recording density of the magnetic tape can be remarkably increased, when considering from a theoretical point of view.
In the servo pattern writer for initially writing servo patterns onto the magnetic tape and the magnetic tape writer for writing/reading data on and from the magnetic tape in the magnetic tape writing system, if the running of the magnetic tape is disturbed above the write head, the writing/reading operation of the servo patterns is erroneous. As a result, the merit of high density recording is not effectively utilized.
Therefore, some contrivance to run the magnetic tape more accurately and stably is required in the servo pattern writer for initially writing servo patterns onto the magnetic tape and the magnetic tape writer for writing/reading data on and from the magnetic tape in the magnetic tape writing system.
Improvement of an operating accuracy of the tape running system in the magnetic tape writer and the like is not easy. Further, such an approach frequently brings about increase of the cost to manufacture.
The tape running stability, if realized through the improvement of the tape running system, does not lead to the improvement of the accuracy in the writing and reading of the servo patterns. The reason for this is that the tape running stability depends greatly on the dimensional accuracy or the like of the tape reels on which the magnetic tape is wound.
In the tape reel 106, the tape edges of the both sides of the magnetic tape 108 wound on the reel hub 110 are positioned by the pair of the upper flanges 112 and 113. In order that a form of the winding of the magnetic tape is kept good with less variation of the tape edge position, a dimension WF between the flanges 112 and 113, as shown in FIG. 10, is selected to be closest to a width dimension WT of the magnetic tape.
If the flange-to-flange dimension WF is too close to the tape width dimension WT, the contact resistance of the tape edges to the flanges 112 and 113 during the tape running is large, however. As a result, the tape running is disturbed, and the writing and reading operations of the servo patterns are frequently erroneous. Particularly when the dimension WF between the paired flanges 112 and 113 is uniform in value over the flange as viewed in the radial direction, the following problem arises. In this case, the diameter of the magnetic tape wound on the tape reel varies, and hence the peripheral speed of the flange varies. Consequently, the contact resistance of the tape edges to the flanges 112 and 113 varies.
If to prevent such a disadvantage, the dimension WF between the flanges 112 and 113 is carelessly increased, the form of the magnetic tape 108 wound on the tape reel 106 is deformed or disfigured.
The magnetic tape cassette is widely used for a recording medium. There are various types of magnetic tape cassettes, such as audio, video and computer tape cassettes. Those types of magnetic tape cassettes may also be categorized into an analog magnetic tape cassette and a digital magnetic tape cassette.
The basic constructions of those magnetic tape cassettes are substantially the same; a magnetic tape, while being movable, is held within a cassette case.
FIG. 15 is a exploded view showing a VHS video cassette as an example of the magnetic tape cassette. A magnetic tape cassette 290 includes an upper cassette half 291 and a lower cassette half 292, each including a flat plate having walls standing erect along its peripheral edge. A couple of tape reels 293 around which a magnetic tape T are rotatably supported within the lower cassette half 292. A transparent reader tape R is jointed to the end of the magnetic tape T. The tape reels 293 are disposed on the lower cassette half 292 such that the magnetic tape T is put between a pair of tape guides 294, which are provided on the front end of the lower cassette half 292.
The lower cassette half 292 and the upper cassette half 291 are combined into the cassette case. The magnetic tape T is exposed through the front end of the cassette case. A guard panel 295 as a cover member is rotatably mounted on the cassette case while covering the front side of the magnetic tape T. An insertion hole 296 is formed at the center of the front end of the flat plate of the lower cassette half 292.
When the magnetic tape cassette 290 or the like is loaded into a magnetic tape drive unit (referred to as a “hard drive”), such as a VTR (video tape recorder), a plurality of positioning pins 300 provided on the hard drive are brought into engagement with predetermined positions (reference positioning means) of the lower cassette half 292. As a result, the magnetic tape cassette 290 is positioned in place within the hard drive.
Recently, with a change of design sense, a transparent or semitransparent product of the skeleton type comes out in the market. In the product, a case of an electric device or the like is translucent so as to allow the inside of the case to be seen from outside. To match such a design trend, there is a demand to make translucent the cassette case made of black or blue resin, which is used in the conventional magnetic tape cassette.
To make translucent the cassette case of the magnetic tape cassette, the strengthening of the resin used and the maintaining of the sliding resistance of the resin come up as the subjects to be solved. Particularly, cut powder that is produced at the contact portion at which the positioning member, e.g., positioning pins 300 comes in contact with the reference positioning means, attaches to the tape, to present various problems, such as drop-out. This leads to deterioration of the product quality.
When the transparency of the resin is increased, the mechanical strength and the wear resistance of the resin are likely to be deteriorated because its physical property.
One possible way to solve the problem is to mix a compound, e.g., additive, with an intention of increasing the resin strength, in the stage of manufacturing the cassette case. This approach, however, brings about the increase of the cost to manufacture, and the product cost.
A magnetic tape cassette is widely used for a recording medium. The magnetic tape cassette is classified into a public-use magnetic tape cassette and a business-use magnetic tape cassette when it is classified on the basis of its use. FIG. 18 is an exploded view showing a mechanical arrangement of component parts in a Beta cam L cassette which is a business-use magnetic tape cassette.
As shown in FIG. 18, the Beta cam L cassette (referred to merely as “magnetic tape cassette”) 370 is made up of an upper cassette half 371 and a lower cassette half 372, a pair of tape reels 373 which are to be wound with a magnetic tape T and located within the upper and lower cassette halves 371 and 372, and a lid 374 which may open and close an opening of the front ends of the upper and lower cassette halves 371 and 372.
Guide rollers 375 and guide pins 377 made of metal, which are wound with the magnetic tape T, are mounted on both sides of the opening of the front end of the lower cassette half 372. The lower cassette half 372, which is in sliding contact with the reverse side of the magnetic tape T, is attached to the lower cassette half 372. Reel springs 379 for urging the tape reels 373 are attached to the upper cassette half 371. The upper and lower cassette halves 371 and 372 are coupled together by means of a plurality of screws 380.
Of those component parts, the guide rollers 375 are made of resin, e.g., POM, which is good in sliding property and mechanical strength. The guide rollers 375 are cylindrical. A rotary shaft pin 376 mounted on the lower cassette half 372 is inserted into the center hole of each of the guide rollers 375. With use of the pins, the guide rollers 375 are rotatably supported on the lower cassette half 372.
FIG. 19 is an enlarged view showing a structure including the guide rollers 375 and the guide pins 377 of the lower cassette half 372 when viewed in the direction of an arrow B in FIG. 18. In FIG. 19, there is illustrated a state of the structure when the magnetic tape T is put on the guide roller 375 and the guide pin 377. Between the tape reel 373 and the guide roller 375, a pad 378 is in sliding contact with the reverse side of the magnetic tape T and urges the magnetic tape T. With this, the magnetic tape T is in sliding contact with the circumferential outer surface of the guide rollers 375. When the reel urging plate spring 370 is loaded to a record/playback apparatus (not shown), and the apparatus is placed to a playback mode or a rewind mode, the magnetic tape T passes the outer surface of the guide rollers 375, is taken out of the cassette case, and is wound on the magnetic head.
FIG. 20 is a cross sectional view taken line in V—V in FIG. 19. The guide rollers 375 are cylindrical and guide the magnetic tape T with their outer surfaces. The upper end face 375a and the lower end face 375b of the guide rollers 375 are brought into contact with the flat plate of the upper cassette half 371 and the flat plate of the lower cassette half 372, respectively.
When the magnetic tape T runs, the guide rollers 75 rotate following up the running of the magnetic tape.
In the magnetic tape cassette as mentioned above, when the guide rollers 375 rotate following the magnetic tape T, the upper end face 375a and the lower end face 375b of the guide rollers 375 are frequently worn. When the guide rollers 375 rotate, and the upper end face 375a and the lower end face 375b of the guide rollers 375 come in sliding contact with the upper cassette half 371 and the lower cassette half 372, cut powder is frequently produced at the contact portions at which the upper end face 375a and the lower end face 375b are brought into contact with the upper cassette half 371 and the lower cassette half 372. The cut powder will cause serious errors, e.g., drop out.
A magnetic tape cassette is widely used for a recording medium. The magnetic tape cassette is classified into audio, video, and computer cassettes and others. Those magnetic tape cassettes may be classified into a public-use magnetic tape cassette and a business-use magnetic tape cassette when it is classified on the basis of its use. Examples of the magnetic tape cassette of the digital type are DAT (digital audio tape) cassette, DVC (digital video cassette), and DDS (digital data storage) cassette. The video magnetic tape cassette may be classified into VHS and Beta video cassettes.
The basic constructions of those magnetic tape cassettes are substantially the same; a tape reel with a magnetic tape wound thereon is housed in a cassette case.
FIG. 22 is a perspective view showing a VHS magnetic tape cassette 440, which is one form of the video magnetic tape cassette. An external appearance of the magnetic tape cassette 440 is substantially defined by an upper cassette half 441 and a lower cassette half 442, each being constructed such that the periphery walls stand erect on a flat plate, and a guard panel 445 as a cover member.
The upper cassette half 441 and the lower cassette half 442 are combined into a cassette case 440a. A couple of tape reels 450 with a magnetic tape T wound thereon are rotatably housed in the cassette case 440a. A label area 447 is provided in the central portion of a flat plate 41a of the upper cassette half 441. A window 446 is located adjacent to the label area 447. The window 446 includes a transparent window member through which a user visually checks a volume of the winding of the magnetic tape T within the cassette case 440a. The magnetic tape is exposed through the front end of the cassette case 440a. 
The guard panel 445 is mounted on the cassette case 440a in a hinged manner, while covering the front end of the magnetic tape T.
As described above, various forms and types of the magnetic tape cassettes are known. Further, the magnetic tape cassettes are classified on the basis of the type of magnetic tape contained and the length of the recording time of the magnetic tape. In the VHS magnetic tape cassette, for example, four types of tape cassettes are used which have the recording time lengths of 30, 60, 120 and 160 minutes.
In the case of the magnetic tape cassette 440, a label 460, which describes a recording time left, the type of cassette (recorded information) and the like, is stuck to the label 460. A label 461 describing a title and the like (recording information) of the contents recorded in the magnetic tape T is stuck to a label area 448, which is located on the rear side wall 440b of the cassette case 440a as the rear end of the magnetic tape cassette 440.
Recently, it is regarded as important to provide advertisement or the like based on user's needs to users, as typically found in the internet advertisement.
The inventor found the fact that useful information will possibly be presented to the user by putting advertisement and the like on the magnetic tape cassette.
A specific implementation of the idea is such that information on movies are visually attached to a magnetic tape storing a video software, which is lent out in a rental video shop, and in this case, the former movies belong to the same genre as of a movie stored in the magnetic tape lent out.